why is this a problem running ubuntu on different computers w/ usb?
 

Yesterday I plugged my usb into a computer with a 6150 series Nvidia card; so to get my programs running smoothly I installed the nvidia 177 driver. everything worked. Today I'm using a computer that has a Intel Q35
and nothing is working; I just read a how to article describing similar problems and deleted the nvidia drivers; now I'm going to reboot, I doubt if this will fix my problem. Does anyone know what to do solution? How can I run Ubuntu 8.10 usb on two computers?

i would use 2 root partitions - one for each computer, and a single partition for /home.
you will have to install each package you want on both of them twice, but you probably can automate this(i don't know how).
you might be able to get away with only a separate /boot and /etc directories, but i wouldn't risk it.

if you do choose to separate the /root directories, you'll need to create two entries in the boot loader and change the "root" argument of the kernel.